1. Field of the Invention
The present invention relates to an audio unit mountable in a personal watercraft (PWC).
2. Description of the Related Art
United States Patent Application Publication No. 2012/0067264 discloses that a personal watercraft (PWC: hereinafter simply referred to as a watercraft) is equipped with an audio unit including a speaker and a sound volume manipulation unit. A rider can adjust a volume of a sound emitted from the speaker suitably by manipulating the sound volume manipulation unit.
During planing of the watercraft, with an increase in an engine speed, a ship speed increases, and an engine noise and a wind noise become louder correspondingly. For this reason, during high-speed planing, the rider cannot hear the sound emitted from the speaker unless the sound volume is adjusted to be considerably higher. When a throttle valve is moved to a closed position in the high-speed planing, the watercraft is decelerated by a body resistance, and the engine noise and the wind noise are diminished. However, regardless of such a quiet environment, a sound with a great volume having been adjusted according to the high-speed planing may be emitted from the speaker undesirably. Since the rider must stabilize the rider's attitude and the body's attitude under a state in which the body resistance and an inertia force are working, during the deceleration of the watercraft, it is very difficult for the rider to reduce the volume of the sound by manipulating the sound volume manipulation unit it in this situation.